ChangeBatchBase.AddChange メソッド

現在開いているグループに、指定された項目変更を追加します。

名前空間: Microsoft.Synchronization
アセンブリ: Microsoft.Synchronization (microsoft.synchronization.dll 内)

構文

'宣言
Public Sub AddChange ( _
    change As ItemChange _
)
'使用
Dim instance As ChangeBatchBase
Dim change As ItemChange

instance.AddChange(change)

public void AddChange (
    ItemChange change
)

public:
void AddChange (
    ItemChange^ change
)

public void AddChange (
    ItemChange change
)

public function AddChange (
    change : ItemChange
)

パラメーター

• change
  現在開いているグループに追加する項目変更です。

例外

解説

項目変更を ChangeBatchBase オブジェクトに追加する前に、BeginOrderedGroup を呼び出すか、ChangeBatch オブジェクトの BeginUnorderedGroup メソッドを呼び出して、グループを開く必要があります。そうしないと、このメソッドによって InvalidOperationException がスローされます。

例

次の例では、変更バッチ内の順序付られているグループに項目を追加して、GetChangeBatch を実装します。項目は、その項目の変更バージョンが同期先ナレッジに含まれていない場合にのみ追加されます。

Public Overrides Function GetChangeBatch(ByVal batchSize As UInteger, ByVal destinationKnowledge As SyncKnowledge) As ChangeBatch
    ' The destination knowledge must be converted to be compatible with the source replica
    ' before it can be used.
    Dim mappedDestKnowledge As SyncKnowledge = _knowledge.MapRemoteKnowledgeToLocal(destinationKnowledge)

    ' Create a new change batch, initialized by using the current knowledge of the source replica
    ' and a new ForgottenKnowledge object.
    Dim changeBatch As New ChangeBatch(IdFormats, GetKnowledge(), New ForgottenKnowledge())

    ' Start a group of changes in the change batch. The group is ordered by item ID.
    ' _getChangeBatchCurrent is 0 the first time GetChangeBatch is called, and is used to track the
    ' position in the metadata store for subsequent calls to GetChangeBatch.
    changeBatch.BeginOrderedGroup(_items.Values(_getChangeBatchCurrent).GlobalId)

    ' itemsAdded is incremented each time a change is added to the change batch. When itemsAdded
    ' is greater than the requested batch size, enumeration stops and the change batch is returned.
    Dim itemsAdded As Integer = 0

    Dim itemMeta As ItemMetadata

    ' Enumerate items and add a change to the change batch if it is not contained in the 
    ' destination knowledge.
    ' _items is a SortedList that contains ItemMetadata objects that are ordered by item ID.
    While itemsAdded <= batchSize AndAlso _getChangeBatchCurrent < _items.Count
        itemMeta = _items.Values(_getChangeBatchCurrent)
        Dim kind As ChangeKind = If((itemMeta.IsDeleted), ChangeKind.Deleted, ChangeKind.Update)
        Dim change As New ItemChange(IdFormats, ReplicaId, itemMeta.GlobalId, kind, itemMeta.CreationVersion, itemMeta.ChangeVersion)

        ' If the change is not contained in the destination knowledge, add it to the change batch.
        If Not mappedDestKnowledge.Contains(change) Then
            changeBatch.AddChange(change)
            itemsAdded += 1
        End If
        _getChangeBatchCurrent += 1
    End While

    ' End the group of changes in the change batch. Pass the current source knowledge.
    changeBatch.EndOrderedGroup(_items.Values(_getChangeBatchCurrent - 1).GlobalId, _knowledge)

    ' When all items in the metadata store have been enumerated, set this batch as the
    ' last batch.
    If _getChangeBatchCurrent = _items.Count Then
        changeBatch.SetLastBatch()
    End If

    Return changeBatch
End Function

public override ChangeBatch GetChangeBatch(uint batchSize, SyncKnowledge destinationKnowledge)
{
    // The destination knowledge must be converted to be compatible with the source replica
    // before it can be used.
    SyncKnowledge mappedDestKnowledge = _knowledge.MapRemoteKnowledgeToLocal(destinationKnowledge);

    // Create a new change batch, initialized by using the current knowledge of the source replica
    // and a new ForgottenKnowledge object.
    ChangeBatch changeBatch = new ChangeBatch(IdFormats, GetKnowledge(), new ForgottenKnowledge());

    // Start a group of changes in the change batch. The group is ordered by item ID.
    // _getChangeBatchCurrent is 0 the first time GetChangeBatch is called, and is used to track the
    // position in the metadata store for subsequent calls to GetChangeBatch.
    changeBatch.BeginOrderedGroup(_items.Values[_getChangeBatchCurrent].GlobalId);
    
    // itemsAdded is incremented each time a change is added to the change batch. When itemsAdded
    // is greater than the requested batch size, enumeration stops and the change batch is returned.
    int itemsAdded = 0;
    
    ItemMetadata itemMeta;

    // Enumerate items and add a change to the change batch if it is not contained in the 
    // destination knowledge.
    // _items is a SortedList that contains ItemMetadata objects that are ordered by item ID.
    for (; itemsAdded <= batchSize && _getChangeBatchCurrent < _items.Count; _getChangeBatchCurrent++)
    {
        itemMeta = _items.Values[_getChangeBatchCurrent];
        ChangeKind kind = (itemMeta.IsDeleted) ? ChangeKind.Deleted : ChangeKind.Update;
        ItemChange change = new ItemChange(IdFormats, ReplicaId, itemMeta.GlobalId, kind, itemMeta.CreationVersion, 
            itemMeta.ChangeVersion);

        // If the change is not contained in the destination knowledge, add it to the change batch.
        if (!mappedDestKnowledge.Contains(change))
        {
            changeBatch.AddChange(change);
            itemsAdded++;
        }
    }

    // End the group of changes in the change batch. Pass the current source knowledge.
    changeBatch.EndOrderedGroup(_items.Values[_getChangeBatchCurrent - 1].GlobalId, _knowledge);

    // When all items in the metadata store have been enumerated, set this batch as the
    // last batch.
    if (_getChangeBatchCurrent == _items.Count)
    {
        changeBatch.SetLastBatch();
    }

    return changeBatch;
}

参照

リファレンス

ChangeBatchBase クラス
ChangeBatchBase メンバー
Microsoft.Synchronization 名前空間